How to Cut Double Wall Stove Pipes

Installing a wood stove through the roof requires the use of a chimney box and double- or triple-wall stovepipes in many areas of the country. Using this kind of stovepipe protects your roof and attic area from fire by keeping the heat away from the wood timbers. You may find yourself with more pipe than you need, which requires you to cut the pipe. Use a special tool to make this job easy, quick and safe.

Things You'll Need

Reciprocating saw

Metal cutting blades

Tape measure

Black crayon or marker

Safety glasses

Thick gloves

Metal file

Duct tape

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Measure the double-wall stove pipe that needs to be cut. Use a black crayon or marker to mark the measurement on the pipe in multiple locations around the pipe. Measure and mark between six to nine times, depending on the pipe's diameter. Connect the marks to form a complete circle around the circumference of the pipe.

Put on safety glasses and thick gloves before beginning the cut. Install a metal cutting blade into a reciprocating saw. Have a helper hold one end of the double-wall stovepipe while wearing gloves as well.

Turn on the reciprocating saw and lightly press the blade into the double-wall pipe. Have your helper turn the pipe as needed to cut all the way around the pipe. Keep the blade moving fast by holding the trigger on the reciprocating saw to avoid hanging up the blade in the metal piping.

Separate the cut section of double-wall stove pipe from the piece to be discarded. Use the saw to cut through any hanging tendrils.

Apply a metal file to any rough edges of the pipe. File around both the interior and exterior cut lines to remove burrs and sharp pieces of metal.

Add duct tape to the cut edge until you are ready to install the double-wall stove pipe. The metal is sharp, and the tape will keep you or others from being cut by it.

Tips & Warnings

Use a wide-mouthed table vise to hold the pipe in place if you don't have a helper. Place a towel or rag on either side of the vise jaws where it grips the metal to avoid making a dent in the stove pipe. Tighten the vise enough to hold the pipe in place while you cut it but not so tight that it bends the pipe.

Always wear safety goggles to prevent bits of metal from flying into your eyes when cutting with the reciprocating saw. Use caution when using cutting power tools.